SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11e2453641ca2eb6d684c88d592e4548f902be7616577ac58e8c92a095204af9' 
  AND token = 'fBi+dPoOjSui6qLef4t5MIkJvHWVdLxVX1ETPn35WHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}